[aprssig] APRS radios

On May 24, 2008, at 4:53 PM, Bob Bruninga wrote:
> APRS is really quite simple. There are only 4 types of packets,
> position, status, message and queries. All one has to do is
> capture them and display them. And provide a simple user interface...
That's a slight bit of an understatement.
I asked about bulletins yesterday. Yep, that's a message packet,
sure, well...maybe just almost, it doesn't have a sequence number.
To fully implement the "message" types of packets, you have to do a
bunch of special bulletin processing. Then you have to think about
third party packets...
Position packets have at least three major variations that I can
think of off the top of my head - raw GPS strings (and two different
strings might be sent), compressed, and MIC-E. Then there are
objects, which is a type of position packet, but...
The thing that makes the APRS spec very difficult to fully implement
is that things were just randomly added on. As a result, people
implement the parts they need to get their immediate need met and
prioritize the other parts as lower priority - because everything in
APRS seems to be a "special case". And as we all know, no software
program every is "finished". (well, except APRSDOS!)
> Interesting to hear you complain. Teenagers have no problem text
> messaging using their phone pads and in fact, seem quite happy with
> it. We have had local/global text messaging and email built into a
> ham radio APRS HT since 1998 (the D7).
I'm no teenager - I don't have the motor control or the
eyesight! :) But I do use a smartphone with keyboard - a much
better design for heavy messaging. The touch tone pad is great for
"mostly telephone calls with some messaging, or a bored teenager".
The keyboard is a better two-way text communication tool.
> In the mean time, I have sure had 10 years an a lot of fun with it...
Yes, me too.
>> Its amazing the kind of communicaitons we can acomplish if we just
> do it...